[PlanetCCRMA] sound card IRQ and crackling sound on F7

[Hector Centeno]

Hi,

I'm having problems with my new motherboard (Asus P5B-VM with an Intel
Core 2 Duo) and a M-Audio Audiphile PCI audio interface. My problem is
mainly with Csound and getting crackling sound on one channel. If I
set jack buffers to anything higher than 512x2 the crackling gets
worse. I tried switching the card to the other PCI slot (it has only
two) and the problem got even worse as I would get crackling audio
always. I noticed that both PCI slots are sharing IRQ with other 3
devices (usb, video card, libata). In the motherboards manual it says:

1.8.2 Configuring an expansion card
After installing the expansion card, configure it by adjusting the
software settings.
1. Turn on the system and change the necessary BIOS settings, if any. See
Chapter 4 for information on BIOS setup.
2. Assign an IRQ to the card. Refer to the tables on the next page.
3. Install the software drivers for the expansion card.

There is no more details about how to perform step 2, Chapter 4 only
talks about reserving IRQ for ISA interfaces and in the bios there is
no way to manually assign IRQs and it looks like it's something you
are supposed to do va software, so I was wondering if anyone knows how
to do IRQ assignment in Linux using the CCRMA kernel. With my older
motherboard and FC6 it was possible to get the Audiophile to have it's
own IRQ and I never had any problems with the audio (until the hard
drive controllers in the mobo started to fail and had to replace it).

Thank you!

Hector